Sudden left lower back pain in pregnancy: 1, if excluded because of trauma caused by the left lower back muscle strains in addition to the pain, may be due to the early stage of pregnancy exercise is too small, all day in bed to rest, did not have a good activity, resulting in blood circulation is not smooth, will cause unilateral lumbar pain phenomenon occurs. This situation will lead to the production of bruises in the pelvic cavity, increased abdominal pressure, and discomfort in the left lower back.2. It is possible that low back pain occurs during the implantation of the fertilized egg in the early stages of pregnancy. So in the early stages of pregnancy suddenly appeared left waist pain symptoms, if after bed rest, if necessary, hot towels outside the left waist. If the symptoms of pain do not improve within a short period of time, or the condition is progressively aggravated, you must go to the regular hospital in time, improve the ultrasound examination, after the cause is clear, choose a reasonable treatment method, so that the symptoms of left waist pain to get timely and effective improvement.